An X-ray is an electromagnetic wave having energy of about 10 eV or greater. Non-destructive testing using X-rays are employed widely in, for example, the industrial and medical fields.
For example, a method for quantitatively obtaining physical property values of a subject in accordance with absorption or phase shift of the X-ray after passing through the subject has been proposed.
PTL 1 discloses a method for obtaining information about electron density distribution and effective atomic number distribution of a subject on the basis of two or more X-ray absorption contrast images using a monochromatic X-ray having two or more energies (wavelengths).
PTL 2 discloses a method for obtaining distribution of an effective atomic number of a subject on the basis of information about absorption and phase shift of an X-ray after passing the subject.